Spoiler
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When Hyosuke mentioned about the scar, he totally change his attitude with you and he wants to flirt immediately. So I assume the prophecy about the scar must not be bad. Like he's trying to persuade you to come to his side. So I expect the prophecy to be some special bond between them romantically? Like one sided love? Or they will kill some evil being together? Or MC will help him solve his problem?
Now he lost one eye and I believe he hates us now? Urgh, too many quesitons! Please stop creating more knots and untie some for us haha